Door mechanism



J. E. WOLF DOOR MECHANISM April 1-0, 1945.,

Filed July 27, 1943 2 Sheets-Sheet 2 IN V EN TOI-T.

Patented Apr. 10, 19.45

,l UNITED STATES PATENT orrlcs DOOR MECHANISM John E. Wolf, Dormont,Pa., assignor to Loftus Engineering Corporation, a corporation ofvMaryland Application July 27, i943, serial No. 496,301

(ol. 11o- 176) 7 Claims.

This invention relates to doors, particularly, though not exclusively,to sliding doors of the type found on certain industrial furnaces, suchas car-bottom furnacesused in the annealing of metal castings, or othermaterial to be heat treated.

The charge-supporting hearth of the -conven tional car-bottom furnace isformed by4 the refractory floor of a car that is adapted to travel onrails through the furnace doorway, between service position within thefurnace and loading y and unloading position. without the furnace.

When the furnace is in operation the door engages at its .upper edge asand seal included in the furnace structure above the furnacedoorway; atits lower edge the door engages a sand seal embodied in the carstructure; and at the two sides of the doorway .the door bears upon acheek plate mounted on the front wall of the furnace and extendingacross the top and down the two sides of the doorway. The door is movandof course it is desirable that the door, when in closed position, shallbe hermetically tight upon the doorway. When the door is closed andopened able vertically between open and closed positions,

no diculty is encountered in establishing and interrupting theengagement of the door with the said seals, but the same does not holdtrue for the engagement of the door with the cheek plate. Under theeffects of the wear and heat to which the door is in service exposed, itis difllcult, if not impossible, to maintain a snug sliding engagementof the edges-of the door upon the cheek plate, and for this reasonfurnace builders have tried various devices for clamping the door to thecheek plate. 'I'he clamping devices hitherto in use are manuallyreleased when it is desired 'to open the door, and manually locked againwhen the door is closed.

The door clamping mechanism of myvinvention operates automatically. Whenthe door is lowered into closed position the mechanism locks itself,clamping the door with equalized pressure to the engaged areas of thecheek plate. Alternately, when the doorvv is raised, the mechanism movesautomatically into release position. It is to be understood that thecapacity of the mechanism to equalize the pressure of engagement of thedoorv over the entire engaged area of the cheek plate is a feature ofnotable value.

In the accompanying drawings Fig. I is a fragmentary view in frontelevation of a furnace door equipped with a clamping mechanism embodyingthe invention;

Fig. II is a vertical sectional view of the same on the plane II-II ofFig. I:

And Fig. III is a sectional view, on the `same plane as Fig. II, showingthe furnace door fragposition,'Fig. II, and open position, Fig. III. The

means for opening and closing the door form no part of the presentinvention, and accordingly are not shown in the drawings. Extendingalong the upper edge of the door is a member 4 that is provided with ablade portion 5 which, when the door is lowered from open to closedposition, em-

beds itself in usual way in a sand seal 6 carried by the front wall ofthe furnace, while the lower edge of the door carries two blades l thatlodge in a sand `seal 8 provided in known way in the body of the car,which is fragmentarily indicated at 9. As thus arranged the door isintended to provide a substantially hermetic closure for the doorway ofthe furnace, but, as above mentioned,

under the conditions of service'the door normally does not seat tightlyagainst'the cheek-plate. `The means of this invention for seating thedoor tightly in closed position in the doorway,

that is, upon the cheek-plate 2 in this case. comprise two sets of cammembers a,l b and a, b. The two sets of cam members are spaced'aparthorizontally, and the two cam members a and b in each set are alignedand spaced apart vertically. Means cooperate with said cam members,

lwhen the door is closed, to secure the door in tightly seated positionof closure, and such means include an arm I0 vfor each c'am member. The

arms I0 are pivotally mounted on a rigid supporting structure. Thesupporting structure may conveniently consist, as herein shown, in thesteel buckstays- I2 of the furnace framework. The

buckstays support bearing blocks I3 in 'which Y shafts Ily arejournaled. The distal ends of the arms Ill are adapted to be engaged bytheir associate cam'members, and preferablythe engagement isanti-frictio'nal, rollers I4 being mounted in the arms for this purpose.In Figs.

scribed, the wedging action of the cam members i a, b upon theiarms iseffective to press the door into tightly seated position against thevcheekplate 2. The door-seating cooperation between A the cam members`a, b and arms I is progressive as the descending door approaches itslowermost or closed position, and as he blades 5 and 1 enter the sand inthe sand seals. By virtue of such feature the effect of the sand inresisting the slight but essential movement of the door towards thecheek-plate is minimized, and of substantially less eifect than it wouldbe if thefdoor were fully closed and the blades fully embedded in thesand before the door-seating pressure was applied. When the door israised into open position, the cam members move upwardly from engagementwith the roller-equipped arms I0, and

it will be understood. that in neither the opening nor the closing ofthe door is there need for any manipulation of the door-seating or`clamping mechanism. The operation is automatic.

The means for limiting the outward rotation of the arms I0, under theeffect ofthe cam members on the door descending into closed position,comprise arms I5 severally secured to the shafts Il. While each arm I5isspaced from the arm I0 on the shaft to which both arms are secured, thetwo arms are in mechanical eilect integral, and extend angularly to eachother, as is shown to best advantage in Figs. II and III. Each pair ofarms I5, thus organized, comprises in effect a bell-crank lever. The twoarms I5 of the pair of levers in each vertically aligned set arepivotally interconnected by a tension rod I6, whose length is adjustableby means of a turnbuckle I1. Manifestly, when the door is loweredintoclosed position, the 'pressure exerted by the upper bell-crank lever ofeach pair or set is trans.- mitted to the 'rod I5, and so is thepressure of the lower cam member on the arm I0 of the lower bell-cranklever. Thus, the pressure on the cam members a, b on the arms IIli ofthe two levers in each vertically aligned pair of levers is equalized.and the door is caused to bear with uniform pressure on all'of the areaof contact of the door with the cheek-plate 2. y

The tension rods I6 also serve to limit the outward turning (acounterclockwise turning as seen in Figs. II and III) of the bell-cranklevers I,' I5 under the effect of the cam members a, b

when the door is lowered into closed position. It will be nosfed thatthe arm I0 of the lower bellcrank lever extends downwardly fromthe axisII on which it turns, while the arm Ill of the companion upper leverextends upwardly. When length of each rod, aords adjustment of the outerlimit of swing of the arms I0.

When the door is fully raised, the mechanism remains in such position asto cooperate with the cam members a, .b when the door is again lowered.The means for holding the disengaged mechanism in such position comprisebrackets I8 welded to the buckstays I2 adjacent to which the rods I6 arelocated, and a spring I9 on each rod between the -turnbuckle and thebracket I8 through which the rod extends; cf. Figs. I and III. As thedoor is lowered, the two lower cam members b on the door engage andswing the arms II! of the upper levers outward beyond the normal limitvof their movement, there beingv hat Athat time no restraint against therise of the rods I6 and the free turning of the lower arms III. scendingdoor thus lengage and pass downwardly from engagement withthe upperbell-crank levers, and presently enter engagement with the lowerbell-crank levers, at which time the upper cam members a on thedoorseverally engage the rollers I4 of the upper levers. All of thelevers are vnow engaged by cam members, andnone of the levers can swingoutward beyond the limit described, the rod I6"tying the two levers ofeach pair or set together, so that one lever in a set cannot movewithout the other. Thus, as the door reaches closed position, therollers I4 on the upper and lower levers provide fixed abut mentsagainst which the cam members bear with wedging effect, and so pressltheedoor into tightly seated position against the cheek-plate 2.

Within the terms of the .appended claims various modifications arepermissible. It will be understood that in the claims the terms upwardand outward are intended to define the arrangement of the cam surfacesof the members a and b for a door that is raised into open position. Ifthe door be one which is lowered into open position, the cam surfaceswill extend outthe door is closing and both levers are subject to theaction of the cam members, the rod I6 restrains or limits the outward`turning of the bellcrank levers, with the consequence that the cammembers wedge against the rollers I4 and press the door into tightlyseated position against the cheek-plates 2. The turnbuckle Il in each'of the bipartite rods IB of the two sets of levers, providing for theadjustment of the effective ward and downward with respect to the planeof the'door, while if the door opens sidewise, the cam surfaces willextend outward and laterally of the door. 'I'he quoted words will beunder stood rto embrace 4these variations. In the same manner, the wordsclockwise and counterclockwise, are intended as words of relationshipand not limitation.

I claim as my invention: l

l. A furnace including a doorway and a furnace door movablesubstantially in the plane of the door between open and closedpositions, two cam members secured to the door in spaced-apart relationin the direction of door movement, said cam members including camsurfaces which slope toward the plane of the door in the direction ofdoor movement towards closed position, a supporting structure, twomembers pivoted to saidsupporting structure in spaced-apart relation inthe direction of door movement, with the space substantially equal tothe space between said cam members, said pivoted members severallyincluding cam-engaging portions extending laterally from the axes oftheir pivots and adapted to rotate on their pivots when, as the .doormoves into closed position, such portions are engaged by said camsurfaces, and means articulated to said pivoted members at points spacedlaterally from the axes of the pivots and interconnecting the pivotedmembers to limit their rotation under the action of said cam surfaces,with the eiect that when the door reaches The lower cam members on thedeclosed position, it is clamped with equalized pressure.

2. The structure of claim 1, said last means comprising a tension memberof variable xed length. I

3. 'I'he structure of claim 1, said pivoted members comprisingbell-crank levers, substantially as described.

4. The structure of claim 1, said pivoted members comprising bell-cranklevers, and said interconnecting means comprising a tension rod ofvariable xed length.

5. The structure of claim 1, said organization of cam members, pivotedmem-bers and' interconnecting means being `provided in two sets thatarespaced apart transversely of the direction of door movement. A

6. A furnace including a. doorway and a furnace movable substantially inthe plane of the door between open and closed positions, two cam memberssecured to the door in spacedapart relation in the direction of doormovement, said cam members including cam surfaces which slope toward theplane of the door in the direc- .tion of door movement toward closedposition, a

supporting structure, two members pivoted to said supporting structurein spaced-apart relation in the direction of door movement, with thespace substantially equal to the space between said .cam members, saidpivoted members severally including cam-engaging portions extending fromtheir pivots one in opposite direction relauvelyfto the other. saidpivoted members. beingrotatable in opposite directions on their pivotswhen, as the door moves into closed position, said portions are engagedby said cam surfaces, and means articulated to said pivoted members atpoints spaced from the axes lof the pivots and interconnecting thepivoted members tolimit their rotation under the eiect of said camsurfaces as the door closes.

7. A furnace including a doorway and a furnace door movable verticallybetween open and closed positions, two cam members secured to the doorsin vertically spaced-apart relation, said cam members including surfacesthat slope downward toward the plane in which the door is movable, -asupporting structure, two members pivoted to said supporting structurein vertically. spaced-apart relation, with the Space substantially equalrto the space between said cam members, said pivoted members. severallyincluding cam-engaging portions extending one upward and one downwardfrom their pivots said pivoted members being rotatable in oppositedirections on their pivots when, as the door movesinto closed position,said portions are engaged by said cam surfaces, and means articulatedtosaid piv- 4 oted members at points spaced from their pivots andinterconnecting the pivotedimembers to limit their rotation under theeffect of said cam surfaces as the door closes.

. l.lOl-IN E. WOLF.

